90 535i A/C Problems

[cga]

I need some help here. My ac will only come on for a minute then turns off, a few minutes later it comes on the same thing. Here is what I have done so far. Replaced dryer, expansion valve and switches, converted to r134(removed ac compressor and drained the put in 5oz of Pag oil) and replace aux low speed resistor. I vacuum system down for 4 hours and check to see if it holds. Check good. If I supply power to the compressor directly it works fine and cools great. I have check all relay and fuses. Sometime it will stay on for five minutes and cools great. The Bently manual refers to a ac compressor clutch control relay which I cannot find. My car was built 8/90. Any Ideas???

Chris

[Jr ///M5]

Are you sure the condenser fan is running when the A/C is switched on?